Hello there,
We apologize that you have encountered this issue when interfacing with the product
There are, however, some red flags in what I read over
The major thing I’m noticing is you’re saying you tried to use 5.0.3 with content you did not convert. This should be expected behavior: That songs that are not converted do not work in 5.0.x.
The point of backing up the files is to easily load them into your SD/internal memory again in the case you want to downgrade. But to actually use them on 5.0.x and later you must convert them.
You cannot use songs that are not in the new format on the new version. This is the point of the conversion. Otherwise, although the Aeros may still see the songs, they will not work once opened.
You really should not worry about converting it has a very very low probability of failure and we ask people to back up their content before in the very slight case something unexpected happens, it is a precaution but not completely necessary. We also have a failsafe measure explained in the forum post and manual.
All we do is create a new meta file for the songs and move the songs into the new albums folder. You can read more about 5.0.3 at the top of the forum thread.
I will also point out, it is generally not good practice to update the version of any product without trying it first if you intend to use it live/in action. I would not update my pro tools right before a recording session has to be done for example.
It is incredibly unfortunate any of this happened but the issue is quite simple, you did not convert the songs and thus they are unusable in 5.0.x.
I would highly encourage you to please convert your content as the update is massive and will improve the use of your Aeros, but you are free to downgrade to any prior version, they are all on the forum.
4.3.1 was the last official version before this.
Thank you for reporting